154229-21-7

17-(3-Pyridinyl)-androsta-4,16-dien-3-one is a possible steroidal inhibitor of human cytochrome P 45017α-hydroxylase-C17,20-lyase.

D4A (Δ4-Abiraterone; 3-Pyridinyl)-androsta-4,16-dien-3-one) is an abiraterone metabolite found to be more active than abiraterone. Abiraterone is a potentselectiveand orally bioavailable inhibitor of CYP17A1 (CYP450c17)an enzyme th at catalyzes two key serial reactions (17 alpha hydroxylase and 17,20 lyase) in androgen and estrogen biosynthesis resulting in the formation of DHEA and androstenedionewhich may ultimately be metabolized into testosterone. CYP17 is the key enzyme for androgen biosynthesis in both the testes and adrenalsso its inhibition can stop the production of androgens in both places. It is approved for the treatment of metastatic castration-resistant prostate cancer. D4A blocks not only CYP17A1but also blocks two other enzymes3?-hydroxysteroid dehydrogenase (3?HSD) and steroid-5?-reductase (SRD5A)which are involved in producing the androgen 5?-dihydrotestosterone (DHT)while also blocking the androgen receptor.